Question

Find all pairs of consecutive odd positive integers both of which are less than 18 and such that their sum is more than 15

Answer 1

Step-by-step explanation:

A) Let the two consecutive odd positive integer be x and x+2.

Both number are smaller than 10 Therefore

x+2<10

Adding −2 to both sides,

=>x<10−2

=>x<8

Also sum of the two integers is more than 11.

So, x+x+2>11

=>2x+2>11

adding −2 to both sides,

=>2x>11−2

=>2x>9

Diving by 2 on both sides,

=>x>9/2

=>x>4.5

Step 2 :

Since x is an odd integer number greater than 4.5 and less than 8 (from 0) x can take values 5 and 7.

Thus the required pairs are (5,7) and (7,9)